Probabilistic characterization of structural demand under earthquake loading - Revisiting the lognormality assumption

Abstract

Probabilistic methods are widely used to assess the performance of structures under earthquake loading and require an adequate probabilistic characterization of the structural demand. Currently, many existing seismic safety assessment studies are developed under the assumption that structural demand conditional to a given seismic intensity follows a lognormal distribution. Given the importance of this assumption, an in-depth analysis of its validity is carried out for several case studies using adequate statistical methods. This assessment of the probabilistic demand distribution type is based on the analysis of 5 reinforced concrete framed structures subjected to sets of 50 real ground motion records scaled to several intensities. The structural demand parameters addressed by the study are the chord rotation, the curvature, the shear force and the inter-storey drift.